MOON AND DUNES: A full moon hangs over the Nebraska Sand Hills. (Photo: Walt Hubis/Flickr)

Some climate activists are declaring victory now that the Obama administration has delayed a decision on the Keystone XL oil sands pipeline until 2013. But regardless of its urgency, climate change alone wasn't enough to sway Uncle Sam. The climate movement succeeded — at least for now — largely because it joined forces with local ranchers, business people, politicians and conservationists in Nebraska.

The State Department made this clear in a press release Thursday, attributing the delay to "the concentration of concerns regarding the environmental sensitivities of the current proposed route through the Sand Hills area of Nebraska." Due to those concerns, the department says it "has determined it needs to undertake an in-depth assessment of potential alternative routes in Nebraska."

Building Keystone XL would launch a long-term commitment to Canadian oil sands, and would likely eliminate some demand for other, cleaner energy sources. But ultimately, that argument may have been too broad, too detached from on-the-ground electoral politics to hold water in Washington.

It's unclear whether Keystone XL will be approved in 2013, so it's unclear what Thursday's announcement really means for climate change. But much like the 2010 Gulf oil spill, the Keystone XL protests did make one thing clear: Environmentalists can still muster nationwide outrage when a specific ecosystem is in immediate danger, especially when that ecosystem is considered a national treasure.

So what are the Nebraska Sand Hills, exactly? They may not be as well-known as the Mississippi Delta, the Everglades or the Chesapeake Bay, but they harbor one of the most pristine wetland ecosystems in the entire Lower 48 states. Not only is the area home to swaths of unspoiled prairie and wetlands — which themselves are home to a diverse menagerie of wildlife — but it also serves as a capstone for the Ogallala Aquifer, a giant underground freshwater source that provides nearly one-third of the country's irrigation groundwater. It also supplies drinking water to 82 percent of people who live within the aquifer boundary, according to the U.S. Geological Survey.

Sand dunes and wetlands can be seen in this satellite photo of the Sand Hills. (Photo: NASA)

Many people in Nebraska, from liberal activists to Republican Gov. Dave Heineman, were vocally concerned about Keystone XL endangering the Sand Hills and the Ogallala Aquifer. A spill could have been disastrous, and since Keystone XL would carry diluted bitumen — a product of oil sands that's more corrosive than ordinary oil — it's not a far-fetched scenario. TransCanada's original Keystone pipeline, which opened in 2010, suffered 11 major leaks within its first year of operation, including one in May that spilled 21,000 gallons in North Dakota. Keystone XL would extend that pipeline to oil refineries along the Gulf Coast, and while the Sand Hills are far from the only natural ecosystem in its path, they are one of the most unique — and most vulnerable.

Grasslands: Native grassland covers 19,600 square miles of wind-deposited sand dunes in the Sand Hills, comprising the largest sand-dune formation in America. An estimated 85 percent of the Sand Hills is still intact and has never been plowed, helping to minimize the fragmentation of animal habitats.

Groundwater: The Sand Hills' dunes act like a "giant sponge," according to the FWS, absorbing precipitation and letting very little escape. As much as half of the region's annual rainfall percolates down to the Ogallala Aquifer, which contains an estimated 1 billion acre-feet of groundwater below the Sand Hills.

Wetlands: The Ogallala Aquifer is vast but also shallow — in many of the Sand Hills' interdunal valleys, the water table rises above the surface to form some of the area's 1.3 million acres of wetlands. This makes the groundwater especially susceptible to hazardous liquids, like oil, spilled on the surface.

Wildlife: The Sand Hills are a key part of North America's Central Flyway for migratory birds, such as the eponymous Sandhill crane. More than two dozen migratory birds "of management concern" visit the area, according to the FWS, and it's also home to 314 animal species and 720 different plants.

For more information about the Sand Hills' ecology, check out this video by nature photographer Mike Forsberg and QUEST Nebraska:

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